Conventional gravity flushing systems generally supply a large amount of the water in the supply tank into the bowl outlet during the flushing operation with relatively small quantities of such water being supplied to outlets around the rim of the bowl. Such systems do not adequately or completely wash the bowl during the flushing operation. The present invention provides an automatically operable diverter valve which is designed to utilize a sufficient quantity of water under line pressure as soon as flushing is initiated to provide a complete pressurized bowl wash.